An electron microstructure study was carried out to understand the precipitation behavior of age-hardening gamma-prime in an iron-nickel base high temperature alloy, Pyromet 860, containing 4 weight per cent cobalt. Carbon extraction replica and thin foil transmission electron microscopy were used. The extraction replica study showed gamma-prime to have many random orientations in addition to some preferred orientation. The thin film microscopy did not show any contrast effect due to coherency strains and confirmed many orientations of gamma-prime precipitates.